1. Field of the Invention
The present invention relates to a high permeability metal glassy alloy for high frequencies which has high electric resistance and high magnetic permeability in a high frequency region.
2. Description of the Related Art
Some of multi-element alloys have the property that in quenching a composition in a melt state, the composition is not crystallized but is transferred to a glassy solid through a super cooled liquid state having a predetermined temperature width. This type of amorphous alloy is referred to as a xe2x80x9cmetal glassy alloyxe2x80x9d. Examples of conventional known amorphous alloys include Fexe2x80x94Pxe2x80x94C system amorphous alloys first produced in the 1960s, (Fe, Co, Ni)xe2x80x94Pxe2x80x94B system and (Fe, Co, Ni)xe2x80x94Sixe2x80x94B system amorphous alloys produced in the 1970s, (Fe, Co, Ni)xe2x80x94M(Zr, Hf, Nb) system amorphous alloys and (Fe, Co, Ni)xe2x80x94M(Zr, Hf, Nb)xe2x80x94B system amorphous alloys produced in the 1980s, and the like. Since these amorphous alloys have magnetism, they are expected to be used as amorphous magnetic materials as molding materials such as a core material of a transformer, and the like.
However, all of these amorphous alloys generally have a super cooled liquid region having a small temperature interval xcex94Tx, i.e., a small difference (Txxe2x88x92Tg) between the crystallization (Tx) and the glass transition temperature (Tg), and must be thus produced by quenching at a cooling rate in the 105xc2x0 C./s (K/s) level by a melt quenching method such as a single roll method or the like. The product has the shape of a ribbon having a thickness of 50 xcexcm or less, and a bulky amorphous solid cannot be obtained.
Examples of metal glassy alloys which have a super cooled liquid region having a relatively large temperature interval, and from which amorphous solids can be obtained by slowly cooling include Lnxe2x80x94Alxe2x80x94TM, Mgxe2x80x94Lnxe2x80x94TM, and Zrxe2x80x94Alxe2x80x94TM (wherein Ln represents a rare earth element, and TM represents a transition metal) system alloys produced in 1988 to 1991, and the like. Although amorphous solids having a thickness of several mm are obtained from these metal glassy alloys, these alloys have no magnetism and thus cannot be used as magnetic materials.
Examples of conventional known amorphous alloys having magnetism include Fexe2x80x94Sixe2x80x94B system alloys. Such amorphous alloys have a high saturation flux density, but sufficient soft magnetic characteristics cannot be obtained. Also these amorphous alloys have low heat resistance, a low electric resistance, and low magnetic permeability in a frequency region of 1 kHZ or more, particularly in a high frequency region of 100 kHz or more, thereby causing the problem of a large eddy current loss in use as a core material for a transformer, or the like.
On the other hand, Co-based amorphous alloys such as Coxe2x80x94Fexe2x80x94Nixe2x80x94Moxe2x80x94Sixe2x80x94B system amorphous alloys and the like have excellent soft magnetic properties. However, such amorphous alloys have poor thermal stability and insufficient electric resistance, thereby causing the practical problem of a large eddy current loss in use as a core material for a transformer, or the like.
Furthermore, amorphous materials can be formed from these Fexe2x80x94Sixe2x80x94B system and Co-based amorphous alloys only under conditions in which a melt is quenched, as described above, and a bulky solid can be formed only by the steps of grinding a ribbon obtained by quenching a melt, and then sintering the powder under pressure. There are the problems of a large number of required steps, and the brittleness of the molded product.
Accordingly, it is a first object of the present invention to provide a high permeability metal glassy alloy for high frequencies, which has a large temperature interval of a super cooled liquid region, which exhibits soft magnetism at room temperature, and which has the possibility that it can be produced in a thicker shape than amorphous alloy ribbons obtained by a conventional melt cooling method, as well as low magnetostriction, high electric resistance, and high magnetic permeability in a high frequency region.
A second object of the present invention is to provide a high permeability metal glassy alloy for high frequencies comprising at least one element of Fe, Co, and Ni as a main component, at least one element of Zr, Nb, Ta, Hf, Mo, Ti, V, Cr and W, and B, wherein the super cooled liquid region has a temperature interval xcex94Tx of 20xc2x0 C. (K) or more, which is represented by the equation xcex94Tx=Txxe2x88x92Tg (wherein Tx represents the crystallization temperature, and Tg represents the glass transition temperature), and the electric resistance is 200 xcexcxcexa9xc2x7cm or more.
The above-described high permeability metal glassy alloy for high frequencies is represented by the following composition formula:
T100xe2x88x92xxe2x88x92yMxBy
wherein T is at least one element of Fe, Co and Ni, M is at least one element of Zr, Nb, Ta, Hf, Mo, Ti, V, Cr and W, 4 atomic %xe2x89xa6xxe2x89xa615 atomic %, and 22 atomic %xe2x89xa6yxe2x89xa633 atomic %.
The high permeability glassy alloy for high frequencies having the above construction preferably has xcex94Tx of 50xc2x0 C. (K) or more, and satisfies the relations 5 atomic %xe2x89xa6xxe2x89xa612 atomic %, and 22 atomic %xe2x89xa6yxe2x89xa633 atomic % in the composition formula T100xe2x88x92xxe2x88x92yMxBy.
The high permeability glassy alloy for high frequencies having the above construction preferably has xcex94Tx of 60xc2x0 C. (K) or more, and satisfies the relations 6 atomic %xe2x89xa6xxe2x89xa610 atomic %, and 25 atomic %xe2x89xa6yxe2x89xa632 atomic % in the composition formula T100xe2x88x92xxe2x88x92yMxBy.
The above-described high permeability metal glassy alloy for high frequencies may be represented by the following composition formula:
(Fe1xe2x88x92axe2x88x92bCoaNib)100xe2x88x92xxe2x88x92yMxBy
wherein M is at least one element of Zr, Nb, Ta, Hf, Mo, Ti, V, Cr and W, 0xe2x89xa6axe2x89xa60.85, 0xe2x89xa6bxe2x89xa60.45, 4 atomic %xe2x89xa6xxe2x89xa615 atomic %, and 22 atomic %xe2x89xa6yxe2x89xa633 atomic %.
The high permeability glassy alloy for high frequencies having the above construction preferably has xcex94Tx of 70xc2x0 C. (K) or more, and satisfies the relations 0xe2x89xa6axe2x89xa60.75, and 0xe2x89xa6bxe2x89xa60.35 in the composition formula (Fe1xe2x88x92axe2x88x92bCoaNib)100xe2x88x92xxe2x88x92yMxBy.
The high permeability glassy alloy for high frequencies having the above construction preferably has xcex94Tx of 80xc2x0 C. (K) or more, and satisfies the relations 0.08xe2x89xa6axe2x89xa60.65, and 0xe2x89xa6b xe2x89xa60.2 in the composition formula (Fe1xe2x88x92axe2x88x92bCoaNib)100xe2x88x92xxe2x88x92yMxBy.
The above-described high permeability metal glassy alloy for high frequencies may be represented by the following composition formula:
CO100xe2x88x92zxe2x88x92vxe2x88x92wxe2x88x92qEzMvBwLq
wherein E is at least one element of Fe and Ni, M is at least one element of Zr, Nb, Ta, Hf, Mo, Ti, V, Cr and W, L is at lease one element of Cr, Mn, Ru, Rh, Pd, Os, Ir, Pt, Al, Ga, Si, Ge, C and P, 0 atomic %xe2x89xa6zxe2x89xa630 atomic %, 4 atomic % xe2x89xa6v xe2x89xa615 atomic %, 22 atomic % xe2x89xa6w xe2x89xa633 atomic %, and 0 atomic %xe2x89xa6qxe2x89xa610 atomic %.
Furthermore, the high permeability metal glassy alloy for high frequencies of the present invention may have a magnetic permeability of 20000 or more at 1 kHz.